The present invention comprises a new and distinct cultivar of Monarda didyma L. known by the varietal name ‘Mondid 0803’. The new variety is a product of a planned breeding program conducted in Germany. The purpose of the breeding program was to develop new powdery mildew resistant cultivars. The new variety was selected as a single plant growing among seedlings from a cross between two unnamed and unpatented Monarda didyma L. plants. The new variety is similar to its parents in habit and flower type, but exhibits powdery mildew resistant. The mildew resistance trait distinguishes ‘Mondid 0803’ as a new and distinct cultivar from others known to the breeder. Asexual reproduction of the new cultivar in Germany by side shoot cuttings has shown that the unique features of the new variety are stable and reproduced true to type in successive propagations by asexual reproduction.